Low-Maintenance Houseplants: Oxalis Triangularis
If you don’t possess the greenest of thumbs, don’t worry! There are plenty of low-maintenance houseplants that thrive with just minimal care, and we’re happy to highlight some of them for you.
First up is the oxalis triangularis. The oxalis family is large and varied, including some rampantly invasive varieties than have given oxalis a bad rep as “garden thugs,” but don’t be too quick to judge all varieties by the bad behavior of a few relatives! Many oxalis varieties are entirely well-behaved and a delightful addition to your home and garden. With varieties hardy in all climates in the United States, there are two that are also good choices for growing indoors as long-lived houseplants – oxalis triangularis and regnelli. Though both are hardy outdoors in zones 6-11, they adapt well to indoor conditions and thrive indoors year round. With its fanciful and intriguing purple foliage, let’s take a closer look at oxalis triangularis.
Oxalis Triangularis Origins
Oxalis triangularis are often referred to as “purple shamrocks.” The plant’s history can be traced back to St. Patrick, who held a similar plant and used the three leaves to explain the concept of the Holy Trinity to the Irish. Oxalis triangularis are not Irish natives, however – instead, they hail from Brazil.
Oxalis triangularis are highly “photophilic,” which means that they open and close not just their blooms, but also their leaves in response to light. At night, neatly folded, oxalis triangularis looks like a cluster of little purple butterflies that then open wide to the morning light. Both the vivid purple color of its leaves and this constant slow motion seems to enchant all who grow it – even “non-gardeners” fall in love this charming beauty. To capitalize on its unusual coloring, containers in silver or chartreuse are especially effective.
Incredibly long lived, oxalis triangularis often become "heirloom plants" passed down from generation to generation within a family. We often hear customers’ stories of the plants becoming a cherished family tradition. One customer told us she was enjoying the same bulbs as their great, great-grandmother who harvested them as a child 107 years ago! Since oxalis triangularis are super simple to plant and grow, they are frequently given as gifts. Choose one of our many pre-planted oxalis gifts, or take it easy on your wallet and make a nice gift by planting four triangularis in an empty soup can with the label removed. Once these are growing, the look is wonderful between the metallic can and deep purple foliage! Let the gift recipient know that these plants have the potential to become treasured, living family heirlooms that will last for generations with little care.
Be aware that oxalis triangularis has developed a natural toxicity to protect it from foraging animals. This is a plant that bites back, so take care with pets and small animals.
Oxalis triangularis bulbs look like small, immature pinecones. When planting a container for indoors, go ahead and crowd your bulbs, spacing them just an inch apart for a full look fast. Just poke the bulbs into the soil – any way up is right. Water lightly just once every couple of weeks until new growth appears. In about 6 weeks from planting, your new purple shamrocks will begin to appear, and will fill in to become lush and full soon after. Weekly watering should be light. Too much water will send the plant back into dormancy.
Indoors, keep your oxalis triangularis in a sunny spot. You will find the deep purple foliage really brings out the vibrant green of other plants, and the color contrast makes your other houseplants seem to glow with health.
Please note that oxalis triangularis occasionally go dormant, looking like the entire plant has died. Because this happens generally during the summer every 2-7 years when the plant is indoors, it seems like a serious problem rather than a periodic event. There is no need to toss your beloved triangularis! Simply stop watering and let the soil thoroughly dry. Set the plant aside where it is no longer center stage, but where you will still see it. In a few weeks, you will see a new leaf emerge. That is the time to resume watering. Soon, your purple shamrocks will be lush and full again.
- Katie Elzer-Peters